Colorimeter Readings Research Articles

Ethnoracial Disparities in Self-Rated Health: Exploring the Impact of Skin Color and Other Ethnoracial Characteristics in Mexico.

This manuscript aims to understand the association between self-rated health and ethnic-racial characteristics (i.e., skin color, self-ascription, and Indigenous language) in the context of the Mexican population. Logistic regression analyses, using the 2019 PRODER (N = 7187)-a representative survey at the national level. We centered the analysis on two measures of skin color: the interviewer assessment of color skin (that has been used in previous studies), and the ITA scale, a measure constructed from optical digital colorimeter readings (a novel method in ethnoraciality studies in Mexico, included in the PRODER survey). In comparison to the interviewer's assessment of skin color, the ITA score shows a significant association with self-rated health, even in the presence of individual conditions, sociodemographic traits, and life-course events. In contrast, ethnic-racial self-ascriptions and speaking of an Indigenous language do not show any statistical associations. Contrary to previous research, our results suggest a positive association between skin color and self-rated health, when the former is assessed with the colorimeter readings; it means that those with lighter color skin are more prone to report a better health perception. It has methodological implications in the way skin color is observed.

A comparison of serum sodium levels measured using a colorimetric kit approach and those determined using direct and indirect ion selective electrode techniques- in a Hospital Central Lab

When electrolyte imbalances are not recognized, they are known to cause severe morbidity and mortality. Dyselectrolytemia is frequently curable. Hyponatremia is a common symptom seen in the elderly. Laboratory equipment may be lacking in rural healthcare settings. As a result, the purpose of this study was to investigate the feasibility of developing a screening technique that can aid in the detection of hyponatremia in such facilities. Serum sodium levels in 120 samples were determined by direct, indirect, and colorimetric ISE. SPSS version 17, NCSS 11, and MINITAB 18 software were used for statistical analysis. Statistical significance was defined as a p-value of 0.05. While comparing the instruments, a basic linear regression analysis was performed, and a regression equation for sodium levels was established. The Bland-Altman analysis yielded a 95% agreement limit between the instruments, which is well within the CLIA-recommended target value of 4 mmol/L in the hyponatremic and normonatremic ranges. The resulting regression equation computes a predicted value for direct and indirect ISE using the colorimeter readings, making it similar to all three instruments in the hyponatremic and normonatremic ranges. The colorimetric method can be used as a low-cost screening technique to identify hyponatremic elderly people for whom a tertiary hospital may be inaccessible, allowing for early care.

Colour assessment of milk and milk products using computer vision system and colorimeter

A computer vision system (CVS) and a colorimeter were compared for their abilities to measure the colour of twenty-seven different milks and milk products. The frequency of similarity test showed that CVS-generated colour chips were similar to the actual sample colour in all trials (100%). The CVS-obtained colours were found to be more similar to the colour of sample visualised on the monitor, compared with colorimeter-generated colour chips, with values of 83.3–100.0% depending on the milk product. The third test showed that there was difference between colour measured by CVS and the colorimeter; colorimeter readings resulted in a darker and yellower colour based on average L∗a∗b∗ values, while CVS readings resulted in lighter and less yellow appearance. Compared with a colorimeter, measuring colour by CVS was, therefore, found to be reliable and should be considered as a superior tool for replacing traditional devices by offering improved representativeness and accuracy.

Comparative assessment of the antimicrobial efficacy of chitosan, ethylenediaminetetraacetic acid, sodium hypochlorite and chlorhexidine against enterococcus faecalis at different irrigant temperatures: An in vitro study

Aim: To evaluate and compare the antimicrobial efficacy of Chitosan, Ethylenediaminetetraacetic acid, Sodium Hypochlorite and Chlorhexidine against Enterococcus faecalis at room temperature of the irrigant, at warm temperature (60o Celsius) of the irrigant and after intracanal heating (180o Celsius) of the irrigant. Materials and method: A total of 120 extracted single-rooted teeth were infected for 21 days with E. faecalis after instrumentation with Pro Taper system. Before irrigation procedure, dentinal shavings were collected in 1 ml of sterile broth and incubated. The optical density of each broth was measured using digital colorimeter and initial readings were recorded. Samples were then divided into five groups of 24 teeth in each group– Group A: Sodium hypochlorite irrigation, Group B: EDTA irrigation, Group C: Chitosan irrigation, Group D: Chlorhexidine irrigation, Group E: Saline irrigation. Each group was further divided into three subgroups – (I) Room temperature of irrigant (II) Warm temperature of irrigant (III) Intracanal heating of irrigant. After irrigation, dentinal shavings were collected and optical density recorded. The values were analysed statistically with Student’s t test and analysis of variance followed by Post-Hoc Bonferroni’s correction test; p-value < 0.05 was considered to be statistically significant. Results: The post irrigation optical densities in all the groups were significantly lower than pre irrigation values. Sodium hypochlorite and Chlorhexidine demonstrated better antimicrobial efficacy followed by Chitosan and EDTA, whereas the least efficacy was shown by Saline which was the control group. Differences in optical density using different irrigants were found to be higher by intracanal heating of irrigants followed by warm irrigation and room temperature irrigation (p

Randomized controlled pilot study of the preoperative use of brimonidine 0.33% topical gel for hemostasis in Mohs micrographic surgery

Brimonidine topical gel may be useful in cutaneous surgical procedures because of its vasoconstricting properties. Assess the hemostatic effect of topically applied brimonidine in patients being treated with anticoagulants and undergoing Mohs micrographic surgery (MMS). Subjects undergoing MMS were randomly assigned to the control (n=10) or study arm (n=14). Controls received standard-of-care MMS, whereas the study arm received the same and preoperative application of brimonidine. Evaluations included rate of blood flow, percentage of wound bed surface area needing electrocautery, and changes in skin colorimeter readings. The treatment arm had 68% less blood loss over 30seconds versus the control arm (P<.05). No patient in the brimonidine arm had more than 50% of the wound bed cauterized versus 80% in the controls. Erythema in the treatment arm was decreased by 3.89 times (P<.01) versus in the control arm. Limitations were small sample size; sites limited to the face; the fact that measurement of bleeding did not account for anesthetic mixed with blood; visual estimation of percentage of wound surface area requiring cauterization; and no measurement of volume of anesthesia, wound depth, or postoperative complications. Preoperative application of brimonidine 0.33% gel may help decrease blood loss and theneed for electrocautery during MMS for patients taking anticoagulants.

Comparative Evaluation of Antimicrobial Efficacy of Neem, Miswak, Propolis, and Sodium Hypochlorite against Enterococcus faecalis using EndoVac

ABSTRACTAimTo compare the antimicrobial efficacy of herbal irrigants neem, miswak, propolis with sodium hypochlorite using conventional needle irrigation and EndoVac irrigation system againstEnterococcus faecalis.Materials and methodsA total of 120 extracted single-rooted mandibular premolar teeth were infected for 21 days withE. faecalisafter instrumentation with ProTaper system. Before irrigation procedure, dentinal shavings were collected in 1 mL of sterile broth and incubated. The optical density of each broth was measured using digital colorimeter and initial readings were recorded. Samples were then divided into four groups of 30 teeth each – Group I: Sodium hypochlorite irrigation, group II: Neem irrigation, group III: Miswak irrigation, group IV: propolis irrigation. Each group was further divided into two subgroups – (a) EndoVac irrigation (b) conventional needle irrigation. After irrigation, dentinal shavings were collected and optical density recorded. The values were analyzed statistically with Student's t test and analysis of variance followed by Tukey's honest significant difference test; p-value &lt; 0.05 was considered to be statistically significant.ResultsThe postirrigation optical densities in all the groups were significantly lower than preirrigation values. Sodium hypochlorite demonstrated better antimicrobial efficacy followed by propolis, neem, and miswak. Differences in optical density values for all irrigants are higher in EndoVac (p &lt; 0.0001) compared with needle (p = 0.0009) group, but it failed to reach statistical significance.ConclusionSodium hypochlorite proved to be a better irrigant followed by propolis, neem, and miswak. EndoVac irrigation system was more effective for elimination ofE. faecalisthan needle irrigation group.How to cite this articleDaga P, Asrani H, Farista S, Mishra P. Comparative Evaluation of Antimicrobial Efficacy of Neem, Miswak, Propolis, and Sodium Hypochlorite againstEnterococcus faecalisusing EndoVac. Int J Prosthodont Restor Dent 2017;7(2):60-65.

Determining the Potential of Colorimetry in Wood Identification

Proper wood identification is the first step in allocating the appropriate utility of the wood species. This is a difficult task for it requires skills gained from a number of years of experience. To come up of with a simple, easy but reliable wood identification technique for unknown wood samples, the study was conducted to determine the feasibility of using colorimetry in identifying different wood species. Solvents used to obtain the wood dye extracts were hot water and ethanol. Light absorbance of the solution was measured using a colorimeter with three (3) light wavelengths particularly 468nm, 520nm and 650nm. Maximum light absorbance of the wood extracts varied significantly among wood samples. This showed that colorimeter readings were able to differentiate one wood sample from the other. Among the three wavelengths, 468 nm was the most successful in segregating the wood samples regardless of the solvent used. Although alcohol gave higher absorbance values, using water as a solvent provided a much clear separation between absorbance values. Hence, hot water should be used instead of alcohol. Besides being readily available, it is safer to handle and much cheaper than alcohol. Keywords - Wood Science, colorimetry in wood identification, wood dye extracts, Philippines

The heritabilities, phenotypic correlations, and genetic correlations of lean color and palatability measures from longissimus muscle in beef cattle

Data from a study conducted over 5 yr were analyzed to determine heritability estimates of LM lean color, as measured by subjective scoring and Hunter Colorimeter readings, and palatability, as measured by trained sensory panelists and Warner-Bratzler shear force (WBSF). Phenotypic and genetic correlations were determined between each of the measures of palatability and color. There were 1,066 cattle representing 12 different breeds in the study. Subjective lean color and a* (redness) and b* (yellowness) values were moderately heritable, 0.34 ± 0.122, 0.29 ± 0.115 and 0.28 ± 0.120, respectively, whereas the L* (lightness) was lowly heritable, 0.09 ± 0.087. The heritability of WBSF was moderately heritable ranging from 0.23 ± 0.114 (3 d) to 0.42 ± 0.148 (21 d). Sustained tenderness, as measured by sensory panelists, was found to be moderately heritable ranging from 0.16 ± 0.108 (21 d) to 0.33 ± 0.135 (14 d). Sustained juiciness and beef flavor, as measured by sensory panelists, were found to be lowly to moderately heritable ranging from 0.00 ± 0.089 (21 d) to 0.18 ± 0.105 (14 d) and 0.00 ± 0.080 (7 d) to 0.18 ± 0.110 (21 d), respectively. The significant phenotypic correlations were those between WBSF and subjective lean color, L* value, and a* value; both initial and sustained tenderness as well as beef flavor were correlated with subjective lean color and L* value. Flavor intensity and overall mouthfeel were associated with subjective lean color, L* value, a* value, and b* value. Both a* and b* values were highly correlated genetically with WBSF, -0.71 and -0.72, respectively, and subjective lean color was moderately correlated with WBSF, -0.46. The genetic correlation between subjective lean color and initial tenderness was also high, 0.56, whereas that between a* value and initial tenderness was 0.43, which was similar to that found between b* value and initial tenderness, 0.44. The genetic correlations between subjective lean color, a* value, and b* value with sustained tenderness were all high at 0.58, 0.70, and 0.58, respectively. The genetic correlations between a* value and b* value with beef flavor were low to moderate at 0.12 and 0.19, respectively, whereas that between subjective lean color and beef flavor was high, 0.64. The genetic correlations between a* value, b* value, and lean color with sustained juiciness were all moderate correlations at -0.35, -0.23, and -0.45, respectively. The genetic correlations between a* value and b* value with overall mouthfeel were high at 0.80 and 0.79, respectively, whereas that between subjective lean color and overall mouthfeel was moderate, 0.46. In conclusion, regardless of measurement technique of lean color, it was not only heritable but was also moderately to highly correlated with measurements of palatability in beef from LM.

In Vitro Evaluation of Tooth-color Change Using Four Paint-on Tooth Whiteners

The effectiveness of four paint-on tooth whiteners was evaluated and compared in this in vitro study. Sixty extracted anterior teeth were selected and randomly assigned to five groups: 1-(AS) Artificial Saliva (Roxane); 2-(MSW) Sparkling White (Meijer); 3-(CNE) Crest Night Effects (Procter & Gamble); 4-(ABB) Beautifully Bright (Avon) and 5-(CSWN) Simply White Night Gel (Colgate-Palmolive). The teeth were cleaned with a soft bristle toothbrush and toothpaste (Procter & Gamble) to remove any residue from the storage solution. The bleaching gels were painted onto the surface of the teeth, and they were then wrapped in gauze moistened with artificial saliva and kept in 100% humidity at 98 degrees F in a laboratory oven (Precision Scientific model 18EG) for 24 hours. The treatment was repeated once a day for 14 days. Visual color assessment was done using a value-oriented Vitapan Classical Shade Guide (Vident) and a colorimeter (Minolta Chroma Meter CR 321). PVS jigs (Exaflex, GC America) were fabricated for each tooth. Visual and colorimetric readings were recorded at baseline, 7 and 14 days. One-way ANOVA and Tukey multiple comparisons test were used to assess differences between groups. CNE and CSWN presented the highest mean number of shade changes and deltaE*ab Colorimeter readings. ABB and MSW did not significantly lighten the teeth, as measured by either method of evaluation after two weeks of the bleaching regimen.

Anthocyanin Levels in Nine Lettuce (Lactuca sativa) Cultivars: Influence of Planting Date and Relations among Analytic, Instrumented, and Visual Assessments of Color

Leaf samples collected from field plots of nine lettuce cultivars established in the early (ES) and late (LS) summer of 2002 and 2003 in Celeryville, Ohio, were subjected to spectrophotometric measurement of anthocyanin concentrations or color analysis based on colorimeter and spectroradiometer readings and human panelist ratings. Interactions among year (Y), transplanting date (TD), and cultivar (C) main effects for anthocyanin concentration were significant as a result of shifts in response magnitude but not direction. Anthocyanin levels were higher after LS than ES transplanting regardless of Y and C. The effects of TD were pronounced in 2002, when differences in average daily temperature between ES and LS transplantings tended to be larger. Also, regardless of Y and TD, anthocyanin levels followed the pattern ‘Impuls’ &gt; ‘OOC 1441’ &gt; ‘Valeria’ &gt; ‘OOC1426’ &gt; ‘Lotto’ &gt; ‘SVR 9634’ &gt; ‘OOC 1434’ = ‘OOC 1310’ &gt; ‘Cireo’. Treatment-based color differences were also evident in colorimeter and spectroradiometer readings. Also, panelists differentiated samples grown in 2003 based on red color intensity. Correlations between analytic and instrumented and human panelist-based measures suggest instrumented assessments of red coloration may serve as proxies for direct measures of anthocyanin levels or human panelist ratings, particularly if the aim is to establish color differences between major experimental groups and assign quantitative, repeatable values to red color intensity.

Planting Date Effects on Anthocyanin Concentrations in Nine Lettuce (Lactuca sativa) Varieties and Relationships among Anthocyanin Levels and Instrumented and Visual Assessments of Color

Leaf samples collected from field plots of nine lettuce varieties established in the Early (ES) and Late (LS) Summer of 2002 and 2003 in Celeryville, Ohio, were subjected to spectrophotometric measurement of anthocyanin concentrations and/or color analysis based on colorimeter and spectroradiometer readings and human panelist ratings. Interactions between year (Y), planting date (PD), and variety (V) main effects for anthocyanin concentration were significant due to shifts in response magnitude, but not direction. Anthocyanin levels were higher following LS than ES planting, regardless of Y and V, and PD effects were pronounced in 2002, when differences in average daily temperature between ES and LS plantings tended to be larger. Also, regardless of Y and PD, anthocyanin levels followed the pattern `Impuls' &gt; `OOC 1441' &gt; `Valeria' &gt; `OOC1426' &gt; `Lotto' &gt; `SVR 9634' `OOC 1434' &gt; `OOC 1310' &gt; `Cireo'. Treatment-based color differences were also evident in colorimeter and spectroradiometer readings. And, panelists differentiated field-grown samples based on red color intensity. Strong correlations between analytical and instrumented and human panelist-based measures suggest that instrumented assessments of red color intensity may serve as reliable proxies for direct measures of anthocyanin levels or human panelist ratings, particularly if the aim is to establish color differences between major experimental groups and assign a quantitative, repeatable value to red color intensity.

The repeatability of an intraoral dental colorimeter

Statement of Problem. Characterizing and reproducing color remain one of the most challenging aspects of dentistry. A relatively new intraoral colorimeter measures the color of natural teeth and metal-ceramic restorations and prints out a color recipe for the Vintage Halo Porcelain System. The reliability of the colorimeter is unknown. Purpose. The purpose of this study was to evaluate the reliability of a contact dental colorimeter and to correlate the shade registered by the colorimeter with the shade selected by experienced clinicians. Material and Methods. In part I of the study, 2 examiners (A and B) took 2 colorimeter measurements from the maxillary right central incisors of 11 subjects. The examiners were blinded to their own data and those of other investigators. The readings were repeated 3 weeks later with the same protocol. The Cronbach α reliability coefficient was used to analyze the collected data. In part II of the study, 2 experienced clinicians (examiners D and E) selected a shade from the classic Vita Lumin Vacuum shade guide for the maxillary right central incisors of the same 11 subjects. The clinicians were blinded to each other's selections and the colorimeter readings. It should be noted that the manufacturer of the colorimeter uses the terms shade, value, and hue to represent chroma, value, and hue, respectively, as defined in the Glossary of Prosthodontic Terms (J Prosthet Dent 1999;81:39-110). Results. The reliability analysis results for each of the combined trials for shade, value, and hue were all >.94. The interexaminer reliability α values were >.9 for shade and value and.64 to.74 for hue. The interexaminer α represented the value range of each of 4 measurements. The intraexaminer reliability α values for shade, value, and hue were.99,.95, and.96 for examiner A and.99,.93, and.97 for examiner B, respectively. In part II of the study, the colorimeter agreed with itself 82% of the time, whereas clinicians agreed with each other on the selected shade 73% of the time. Selections made by the colorimeter and the clinicians matched 55% to 64% of the time. Conclusion. Within the limitations of this study, the colorimeter reliably measured the color of natural teeth. (J Prosthet Dent 2002;88:585-90.)

Relationships among glycolytic potential, dark cutting (dark, firm, and dry) beef, and cooked beef palatability.

One hundred beef carcasses were selected at three packing plants and were used to determine the relationship between glycolytic potential (GP) and dark, firm, and dry (DFD) beef and to determine the effects of DFD status and GP on cooked beef palatability. Eight individual muscles were excised from one hindquarter of each carcass at d 7 postmortem: longissimus lumborum, psoas major, gluteus medius, tensor fasciae latae, rectus femoris, semimembranosus, biceps femoris, and semitendinosus. Ultimate pH, colorimeter readings, and Warner-Bratzler shear force were determined for all eight muscles at d 7 postmortem. A nine-member trained sensory panel evaluated cooked longissimus lumborum, gluteus medius, and semimembranosus steaks. Traits determined solely for the longissimus lumborum were GP (2 x [glycogen + glucose + glucose-6-phosphate] + lactate) and ether-extractable fat. A curvilinear relationship existed between GP and ultimate pH within the longissimus muscle. There appeared to be a GP threshold at approximately 100 micromol/g, below which lower GP was associated with higher ultimate pH and above which GP had no effect on ultimate pH. The greatest pH and muscle color differences between normal and DFD carcasses were observed in the longissimus lumborum, gluteus medius, semimembranosus, and semitendinosus muscles. Cooked longissimus from DFD carcasses had higher shear force values (46% greater) and more shear force variation (2.3 times greater variation) than those from normal carcasses. Dark cutting carcasses also had higher shear force values for gluteus medius (33% greater) and semimembranosus (36% greater) than normal carcasses. Sensory panel tenderness of longissimus, gluteus medius, and semimembranosus was lower for DFD carcasses than for normal carcasses. Longissimus and gluteus medius flavor desirability scores were lower for DFD than for normal carcasses. Steaks from DFD carcasses had more off-flavor comments than steaks from normal carcasses, specifically more "peanutty," "sour," and "bitter" flavors. The DFD effect of higher shear force values was approximately five times greater (+3.11 kg vs +0.63 kg) for carcasses with "slight" marbling scores than for carcasses with "small" marbling scores. In general, higher GP was associated with increased tenderness, even among normal carcasses. In conclusion, low GP was associated with DFD beef and resulted in substantially less-palatable cooked steaks.

Lycopene content differs among red‐fleshed watermelon cultivars

AbstractLycopene, a carotenoid, has antioxidant properties that may reduce the incidence of certain cancers. Watermelon (Citrullus lanatus (Thunb) Matsum &amp; Nakai) is a natural source of lycopene, with a reported average content of 48.7 µg g−1 fresh weight based on samples taken from retail produce. This study demonstrated the variability of lycopene content in 11 red‐fleshed watermelon cultivars grown at one location, representing seedless, open‐pollinated and hybrid types, and in commercially shipped hybrid and seedless melons, representing seasonal production periods. Tristimulus colorimeter a* and chroma values were positively correlated with lycopene values, but linear or quadratic regressions of colorimeter data against lycopene values were not significant. Tristimulus colorimeter readings from cut melons were compared to amounts of lycopene extracted from the same melons. Lycopene content varied widely among cultivars, with four cultivars having mean values greater than 65.0 µg g−1 fresh weight. Seedless types sampled tended to have higher amounts of lycopene (&gt;50.0 µg g−1 fresh weight) than seeded types. Watermelon lycopene content changed for some cultivars with production season.Published in 2001 for SCI by John Wiley &amp; Sons, Ltd

A survey of beef muscle color and pH.

The objectives of this study were to define a beef carcass population in terms of muscle color, ultimate pH, and electrical impedance; to determine the relationships among color, pH, and impedance and with other carcasses characteristics; and to determine the effect of packing plant, breed type, and sex class on these variables. One thousand beef carcasses were selected at three packing plants to match the breed type, sex class, marbling score, dark-cutting discount, overall maturity, carcass weight, and yield grade distributions reported for the U.S. beef carcass population by the 1995 National Beef Quality Audit. Data collected on these carcasses included USDA quality and yield grade data and measurements of muscle color (L*, a*, b*), muscle pH, and electrical impedance of the longissimus muscle. About one-half (53.1%) of the carcasses fell within a muscle pH range of 5.40 to 5.49, and 81.3% of the carcasses fell within a longissimus muscle pH range of 5.40 to 5.59. A longissimus muscle pH of 5.87 was the approximate cut-off between normal and dark-cutting carcasses. Frequency distributions indicated that L* values were normally distributed, whereas a* and b* values were abnormally distributed (skewed because of a longer tail for lower values, a tail corresponding with dark-cutting carcasses). Electrical impedance was highly variable among carcasses but was not highly related to any other variable measured. Color measurements (L*, a*, b*) were correlated (P < 0.05) with lean maturity score (-.58, -.31, and -.43, respectively) and with muscle pH (-.40, -.58, and -.56, respectively). In addition, fat thickness was correlated with muscle pH and color (P < 0.05). There was a threshold at approximately .76 cm fat thickness, below which carcasses had higher muscle pH values and lower colorimeter readings. Steer carcasses (L* = 39.62, a* = 25.20, and b* = 11.03) had slightly higher colorimeter readings (P < 0.05) than heifer carcasses (L* = 39.20, a* = 24.78, and b* = 10.80) even though muscle pH was not different between steer and heifer carcasses. Dairy-type carcasses (pH = 5.59, L* = 37.56, a* = 23.40, and b* = 9.68) had higher muscle pH values and lower colorimeter readings than either native-type (pH = 5.50, L* = 39.55, a* = 25.13, and b* = 11.00) or Brahman-type (pH = 5.46, L* = 39.75, a* = 25.17, and b* = 11.05) carcasses (P < 0.05).

Quantification of Watermelon Lycopene Content and Correlation with Colorimetric Measurements

The red flesh of watermelon contains lycopene, a pigment with antioxidant properties that help prevent certain types of cancers. This experiment was done to determine cultivar variation in lycopene content, and the effectiveness of colorimetric measurements for predicting lycopene content. Ten ripe melons per cultivar of hybrid, open-pollinated, and triploid types were selected from field plantings at Lane, Okla. Melons were cut transversely and color measured with a colorimeter at three heart and three locule sites, in a counterclockwise rotation starting at the ground spot. For lycopene content, a 100-g sample of heart tissue was removed, extracted with a hexane-acetone-ethanol mixture, and lycopene concentration measured spectrophotometrically at 503 nm. Lycopene content varied among cultivars, from 33.96 μg·g–1 in `Crimson Sweet' to 66.15 μg·g–1 in `Crimson Trio'. Chroma and “a” colorimeter values were highly correlated with lycopene content (P &lt; 0.001). Linear and quadratic regression of lycopene against colorimeter values yielded an R2 of 0.55. Results indicate that, like tomatoes, watermelon cultivars vary widely in lycopene content. Colorimeter readings did not adequately predict lycopene values.

099 Browning Inhibition of Fresh-cut `Anjou' and `Bartlett' Pears

A treatment to inhibit browning and maintain quality of fresh-cut `Anjou' and `Bartlett' pears (Pyrus communis L.) was developed. Slices of ŒAnjou, and ŒBartlett, pears with a range of initial firmness values were dipped in mixtures of 4-hexylresorcinol, isoascorbic acid, potassium sorbate, and N-acetylcysteine before refrigerated storage. Browning, as indicated by visual observation and by colorimeter readings, was inhibited for 14 d. Pears receiving the antibrowning treatment maintained firmness as well or better than the control slices.

Using measurements of muscle color, pH, and electrical impedance to augment the current USDA beef quality grading standards and improve the accuracy and precision of sorting carcasses into palatability groups.

This research was conducted to determine whether objective measures of muscle color, muscle pH, and(or) electrical impedance are useful in segregating palatable beef from unpalatable beef, and to determine whether the current USDA quality grading standards for beef carcasses could be revised to improve their effectiveness at distinguishing palatable from unpalatable beef. One hundred beef carcasses were selected from packing plants in Texas, Illinois, and Ohio to represent the full range of muscle color observed in the U.S. beef carcass population. Steaks from these 100 carcasses were used to determine shear force on eight cooked beef muscles and taste panel ratings on three cooked beef muscles. It was discovered that the darkest-colored 20 to 25% of the beef carcasses sampled were less palatable and considerably less consistent than the other 75 to 80% sampled. Marbling score, by itself, explained 12% of the variation in beef palatability; hump height, by itself, explained 8% of the variation in beef palatability; measures of muscle color or pH, by themselves, explained 15 to 23% of the variation in beef palatability. When combined together, marbling score, hump height, and some measure of muscle color or pH explained 36 to 46% of the variation in beef palatability. Alternative quality grading systems were proposed to improve the accuracy and precision of sorting carcasses into palatability groups. The two proposed grading systems decreased palatability variation by 29% and 39%, respectively, within the Choice grade and decreased palatability variation by 37% and 12%, respectively, within the Select grade, when compared with current USDA standards. The percentage of unpalatable Choice carcasses was reduced from 14% under the current USDA grading standards to 4% and 1%, respectively, for the two proposed systems. The percentage of unpalatable Select carcasses was reduced from 36% under the current USDA standards to 7% and 29%, respectively, for the proposed systems. These grading systems, which included requirements for maturity, marbling, hump height, and colorimeter readings, could be implemented into the current USDA beef quality grading standards and improve the accuracy and precision of sorting beef carcasses into palatability groups. At the least, measurements of muscle color or pH could be used in a branded-beef program to increase the palatability consistency of its beef products.

360 Quality Deterioration of Fresh-cut Onions

A study on quality changes of fresh-cut onions under different temperatures and handling conditions was conducted. High-quality onions were peeled and diced into 1 x 1 cm pieces. Replicated (3) experimental units (150 g) were stored for 20 days in glass jars in a humidified air flow under the following conditions: 0, 5, and 10 °C. To simulate rough handling, onion pieces were rolled with a rolling pin with enough pressure to induce some damage and stored at 5 °C. Objective (color, soluble solids, and dry and fresh weights) and subjective (visual quality, decay, aroma, and discoloration) measurements were taken every 5 days. Fresh and dry weights as well as soluble solid content decrease with storage time and temperature, but decay and development of off-odors increased. An overall browning was observed at the higher temperatures. Colorimeter readings indicate that b* and chroma increased with storage and temperature, while a* values decreased. No definite trends were observed in L* values, and no major differences were found in the hue, although hue tend to be higher with lower temperatures. Rough handling resulted in a faster quality deterioration rate in comparison with pieces stored at the same temperature. At 0 °C, diced onions could be stored satisfactorily for 20 days, although some quality changes took place. At 5 °C visual quality may be acceptable after 10 days of storage, but discoloration started to show up after 5 days, reducing acceptability. Storage at 10 °C only is possible for very short periods of time. Rough handling increases the rate of quality deterioration.

Measuring muscle color on beef carcasses using the L*a*b* color space.

Because beef muscle color affects consumers' purchasing decisions, is a factor in determining USDA grades, and has been shown to be useful in sorting carcasses according to palatability, this study was conducted to determine the effects of measurement conditions on L*, a*, and b* values, to determine the relationships among USDA quality grading factors, muscle pH, electrical impedance, and colorimeter readings, and to develop a classification system that could be used to sort beef carcasses with respect to muscle color. Data were collected over 2 d from 145 beef carcasses in a commercial packing plant. The exposed longissimus muscle at the 12th/13th rib was used for all muscle pH, electrical impedance, and colorimeter measurements. A Minolta Chroma Meter CR-310 was used to obtain L*, a*, and b* readings. Bloom time, from 0 to 93 min, had a greater effect on a* and b* readings than on L* readings. The L* values stabilized after approximately 30 min bloom time, and a* and b* values stabilized after 78 min bloom time, but relative differences among carcasses in L*, a*, and b* values did not change after 3 to 12 min bloom time. Days postmortem, cut surface (anterior versus posterior), and within-muscle location (medial vs lateral) did not affect L*, a*, and b* readings (P > .05). Blotting the surface moisture from the longissimus muscle resulted in lower a* readings (P < .05), but did not affect L* and b* readings (P > .05). The L*, a*, and b* values were correlated with lean maturity scores (-.67, -.30, and -.40, respectively), dark cutter discount (-.60, -.76, and -.73, respectively), muscle pH (-.57, -.79, and -.78, respectively), and electrical impedance (-.27, -.21, and -.25, respectively). Two muscle color classification systems, nine classes each, are proposed, one system based on L* and one system based on b*. The main advantage of the L* categorization system over the b* system is that the L* value was less sensitive to bloom time, and the main advantage of the b* categorization system over the L* system is that the b* system was slightly more precise at segregating carcasses based upon corresponding differences in muscle pH. This research provides procedural guidelines for measuring beef muscle color and shows that a colorimeter can effectively aid researchers and graders in assessing beef carcass quality.